d-jnki-1 and Nerve-Degeneration

JNKs (c-Jun N- terminal kinases) are important transducing enzymes involved in many faces of cellular regulation such as gene expression, cell proliferation and programmed cell death. The activation of JNK pathway is critical for naturally occurring neuronal death during development as well as for pathological death of adult brain following different insults. In particular, JNKs play an important role in excitotoxicity and all related phenomena. Initial research concentrated on defining the components and organization of JNK signalling cascades, but more recent studies have begun to see JNK as the appropriate target for prevent cell loss. We used a specific JNK inhibitor, the cell permeable peptide D-JNKI1, to block JNK action in neuronal death following excitotoxicity in vitro and cerebral ischemia in vivo. Here we review our recent findings and we discuss the possibility of using D-JNKI1 as a therapeutic agent to prevent cell loss in the central nervous system.

Topics: Animals; Central Nervous System; Disease Models, Animal; Enzyme Inhibitors; Hippocampus; Humans; Ischemia; MAP Kinase Kinase 4; Mice; Nerve Degeneration; Neurodegenerative Diseases; Neurons; Peptides; Rats

The c-Jun N-terminal kinases (JNKs) are also called stress activated protein kinases (SAPKs) and are members of the family of mitogen activated protein kinases (MAPKs). While the functions of the JNKs under physiological conditions are diverse and not completely understood, there is increasing evidence that JNKs are potent effectors of apoptosis of oxidative stress-damaged cells in both the brain and the mammalian inner ear following a trauma. The activation of the inducible transcription factor c-Jun by N-terminal phosphorylation is a central event in JNK-mediated apoptosis of oxidative stress-damaged auditory hair cells following exposure to either acoustic trauma or a toxic level of an aminoglycoside antibiotic and also the apoptosis of auditory neurons as a consequence of a loss of the trophic support provided by the auditory hair cells. In this review, we summarise what is known about the expression and activation of G-proteins, JNKs, c-Jun and c-Fos under oxidative stress conditions within the mammalian cochlea. A particular focus is put on a new peptide conjugate that is a promising protective agent(s) and pharmacological strategies for preventing cochlear damage induced by both acoustic trauma and aminoglycoside ototoxic damage.

Topics: Aminoglycosides; Animals; Apoptosis; Deafness; Hair Cells, Auditory; Humans; MAP Kinase Signaling System; Nerve Degeneration; Noise; Oxidative Stress; Peptides